Sick silkie roo...questions about silkie hen

Posted a few weeks ago without much response. Have a very sick silkie roo. From researching I think it may be Mareks but have some other questions.

3 weeks ago noticed limp in roo, checked for bumblefoot found nothing.
Since then, barely eating or drinking, just stands and sleeps with paralyzed foot out, head is down, tail feathers down too, eyes look ok when he looks up at you or you hold him. Breathing seemed fine also, vent area - not sure but it looked ok. Removed him from the other silkie hen as soon as we noticed the limp. I can't bare to cull him.

He was in an area with a silkie hen. She was separated to another pen but not far away. They did not free range much in the nicer weather, always stuck to a very small area. Wondering what to do about her eggs. She seems fine, no symptoms at all and laying regularly. Advice on this?? I know the roo is dying I dont know what to do about her or her eggs. They were raised together since we got them at 2-3 months old. I'm thinking whatever he had he got from the previous farm. I also have 6 other chickens in the coop who have not had any contact with them. They all are fine.

This is our first year with chickens. Its devastating to watch this poor guy slipping away and not know what caused it and what to do going forward. Would appreciate any advice.

Sorry I'm new to this to and lost my Polish hen last week after no reply. did try things I saw on this site like giving it baking soda and water thought she was doing better she even ate that night tried yogurt to and cottage cheese she ate these but after three days found her dead one morning. Wish I was more help I do know they get some kinda scale on there feet and legs and there medicine for it. I took my very first sick chick to a vet and got all kinds of antibiotics and just prolonged the inevitable for two weeks. I know for parrots,I have one they prescribe beniback not sure how its spelled but its an immune booster. I'm still not sure why my chicken died she seemed fine up till the day I found her inside the coop instead of in the outside pen I check on them twice a day. So I hope your outcome is much better than mine. Good luck.